Abstract
PURPOSE: To compare patients with generalised joint hypermobility (GJH) who sustained a second anterior cruciate ligament (ACL) injury with those who did not sustain a second ACL injury, in terms of muscle strength, psychological response and level of knee-strenuous activity after primary ACL reconstruction. We hypothesised that patients who sustained a second ACL injury would display similar muscle strength symmetry, report similar psychological response and report greater levels of knee-strenuous activity compared to patients who did not sustain a second ACL injury. METHODS: Data from a rehabilitation specific registry were extracted. Patients 15-30 years old with GJH, who sustained a second ACL injury after primary ACL reconstruction were matched 1:2 with patients with GJH who did not sustain a second ACL injury. Outcomes were compared at the 10-week, 4-, 8- and 12-month follow-ups after primary ACL reconstruction. Outcomes comprised limb symmetry index and peak torque relative to body weight for quadriceps and hamstrings muscle groups assessed seated isokinetically with a Biodex. In addition, the questionnaires knee self-efficacy scale(18), ACL-return to sport after injury scale and Tegner activity scale (Tegner) were analysed. All outcome data were analysed with the independent t-test, except for the Tegner which was analysed with the Mann-Whitney U-test. RESULTS: Thirty-two patients sustained a second ACL injury and were matched with 64 patients who did not. The mean age at time of ACL reconstruction was 19 ± 3 years, and 58 (60%) were female. There were no differences in muscle strength between groups at any follow-up. At the 8-month follow-up, patients with a second ACL injury reported higher on ACL-return to sport after Injury (65.6 ± 17.9 vs. 53.5 ± 17.3, p = 0.006), and participated in gknee-strenuous activity (median Tegner 5.0, interquartile range [IQR]: 3.0 versus 4.0, IQR: 4.0, p = 0.046) compared to patients without a second ACL injury. CONCLUSION: Patients with GJH who sustained a second ACL injury reported greater confidence, lower negative emotions, and lesser risk appraisal towards return to sport, and reported greater levels of knee-strenuous activity at 8 months after primary ACL reconstruction compared to matched patients who did not sustain a second ACL injury. These findings might suggest that patients who report greater psychological readiness to RTS, that is, greater confidence, lower negative emotions and lesser risk appraisal, at 8 months, need more cautious guidance when increasing knee-strenuous activity. LEVEL OF EVIDENCE: Level IV, cross-sectional study.